* GOES-16 data posted on this page are preliminary, non-operational and are undergoing testing *

During the week of 19 July – 26 July 2017, the Upper Midwest was affected by a number of strong to severe Mesoscale Convective System (MCS) events, as shown in an animation of GOES-16 “Clean” Infrared Window (10.3 µm) images (above).

At the beginning of that time period, a derecho moved across the region on 19 July producing widespread damaging winds, large hail and a few tornadoes (blog post).

Following the derecho, a separate outbreak of thunderstorms exhibited well-defined “enhanced-V” storm top signatures in western Wisconsin (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

Another MCS produced tornadoes and damaging winds across eastern Iowa and northern Illinois on 21 July (SPC storm reports) — at one point a storm in northern Illinois exhibited a seldom-seen “warm trench” surrounding an overshooting top (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

Early in the day on 23 July, “transverse banding” — a signature indicating the likelihood of high-altitude turbulence — was seen around the northern periphery of an MCS that was centered in southern Illinois (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

A pattern of mesoscale banding was displayed by thunderstorms that produced localized 1-2″ amounts of rainfall across southern Wisconsin on 26 July (below).

GOES-16 Infrared Window (10.3 µm) image [click to enlarge]

Also noteworthy was the swath of very heavy rainfall during this 1-week period across eastern Iowa, far southwestern Wisconsin and northern Illinois (below), which was responsible for flash flooding in those areas.

7-day total precipitation, departure from normal and percent of normal [click to enlarge]